Electronic equipment requires a source of electrical power to operate. Typically, electrical power is obtained from AC power lines, and processed through one or more power supply circuits to provide power at the particular voltage levels that the electronic equipment requires. To minimize the likelihood that the equipment will be unavailable due to a failure of a power supply circuit, often a spare power supply circuit is provided which can be switched in to provide power in the event one of the power supply circuits fails. Providing a spare power supply circuit can ensure continuous availability of the electronic equipment, but it can also increase the cost. In addition, before a failed or failing power supply circuit is switched out, sometimes variations in voltage of the power supplied thereby can make operation of the electronic equipment powered thereby unreliable. Further, the operation of switching a failing power supply circuit out and the spare power supply circuit in can cause undesirable voltage transients which can also make operation of the electronic equipment unreliable.